Claude audits and fixes your Excel model without seeing a single name

Hidden Tokens · Excel · Claude Desktop · fictitious workbook

Your client’s margin model can’t go to an AI: real company names, real people. With Hidden Tokens it doesn’t have to. The workbook is read on your computer. Claude gets codes instead of names, and the fixes are written back into the real file, on your side.

1. The audit, run on your computer

You ask Claude to check the workbook. Hidden Tokens reads the real file locally, with the real values, and hands Claude only cell addresses, coded sheet names and formulas. This is the real output on our demo workbook:

🩻 WORKBOOK AUDIT — 2 sheet(s), 27 formula(s), 94 cell(s) read ON THIS COMPUTER with the real values.
5 finding(s): 3 serious, 2 to check, 0 for information.
[SERIOUS] formula that breaks the pattern of its column or row — sheet « Margins Q3 », F7: found =D7-E6, expected =D7-E7 (series F2:F12).
[SERIOUS] range that stops before the end of the data — sheet « Margins Q3 », D12: D2:D9 stops before D10 — 2 filled cell(s) left out (=SUM(D2:D9)); proposed fix =SUM(D2:D11).
[SERIOUS] displayed result no longer matches its formula (not recalculated) — sheet « Margins Q3 », E12.
[CHECK] value typed in the middle of a series of formulas — sheet « Margins Q3 », G9: a value instead of the series' formula (expected =F9/D9).
[CHECK] number stored as text (ignored by SUM) — sheet « Margins Q3 », E10

2. What Claude actually sees

Companies and people become codes. Amounts stay readable, because they rarely identify anyone and the AI needs them to calculate; any column can be switched to placeholder values. The formulas come along, coded the same way, and the copy is recalculated on its own numbers so every total still adds up.

Client       Account manager  Region  Revenue  Cost     Gross margin  Margin %
COMPANY-001  PERSON-001       North   184,000  121,500  62,500        34.0%
COMPANY-002  PERSON-002       Coast    96,500   58,200  38,300        39.7%
COMPANY-003  PERSON-001       North   241,000  187,300  53,700        22.3%
…
F7   =D7-E6
D12  =SUM(D2:D9)
G12  =F12/D12

3. The fix, applied to the real file

Claude proposes the corrections and, with your agreement, Hidden Tokens applies them to the real workbook: codes translated back, formatting, charts, pivots and macros kept, every changed cell highlighted, and the original never overwritten.

✅ Corrected workbook written on this computer.
4 cell(s) changed in 1 sheet(s) — 3 formula(s), 1 value(s) — highlighted in pale yellow; full recalculation on open. The original is untouched.
Cells: Margins Q3!F7, Margins Q3!G9, Margins Q3!E10, Margins Q3!D12.

Audit the corrected file again and nothing is left: the five findings are gone.

What the audit checks

Formulas that break their series: one cell of a column refers to the row above, or to the wrong column.
Ranges that stop short: a SUM that ends two rows before the data does.
Values typed over a formula in the middle of a column of formulas.
Stale results: the value shown no longer matches what the formula gives.
Errors, circular references, links to other workbooks, numbers stored as text, hidden sheets, rows and columns.

What we don’t claim

This is pseudonymization, not anonymization: the key reverses it, and it stays on your computer. Amounts are readable unless you choose otherwise. The recalculation covers about 70 common functions; anything else is reported as not recalculated, never guessed. A protected number keeps its formula in the coded copy only if the formula can’t give its real value away. Copilot in Excel reads workbooks directly: Hidden Tokens doesn’t sit in front of it.

Try it

Mac and Windows, with Claude Desktop. 14-day trial, no account, no card. Nothing ever reaches us: no server, the licence is checked offline.

Download — 14-day trial The demo workbook (.xlsx, fictitious)

The demo workbook is entirely made up: companies, people and amounts. Put it in your Hidden Tokens folder and ask Claude: “Audit my Q3 margins workbook.”